Heat exchange device



July 4, 1939. F. J. FETTE 2,165,094

HEAT EXCHANGE DEVICE fljmk .Felde July 4, 1939. F. .3, FETTE l 2,165,094

HEAT EXCHANGE DEVICE Filed Aug. 2.6, `1936 4-SheetsSheet 2 July 4, 1939.y F, J, FET-rE 2,165,094

HEAT EXCHANGE DEVICE Filed Aug. 26, 1936 4 Sheets-Sheet 3 y f 5mm Emawww F. J. FETTE HEAT EXCHANGE DEVICE lJul), 4, 1939.

Filed Aug. 426, 1936 4 Sheets-Sheet 4 gmc/mw,

' rank Bite l Patented July 4, 1939 UNITED STATES HEAT EXCHANGE DEVICE yFrank J. Fette, Tampa, Fla.

Application August 26, 1936, Serial No. 97,922

7 Claims.

heat-transfer units in which the surface to bev exposed to the liquidto'be treated may be formed from smooth, thin plates of stainlesssteelor other vnon-corrodible materials.

Other objects of the invention will appear in the description of thepreferred embodiments of the invention illustrated in the drawingsforming a part of this specification, in which Figure 1 is an elevation,with parts in section and-parts broken away, of an assembly forIpasteurizing,

cooling, and chilling milk; Fig. 2 isa plan View of the deviceof Fig. 1;Fig. Sis a plan view of a" plate forming one surface of a unit; Fig. 4is an elevation with parts in section of a device for carbonatingbeverages; Fig. 5 is a transverse section on an enlarged scale of theelements in a single tank of the structure of Fig. 1; Fig. 6 is asimilar transverse section of a modification of the sameelements; Fig. 7is a longitudinal view with portions in elevation and portions insection of a modification in which the assembly of units is completelyenclosed; and Fig. 8 is a transverse section in two different planes, onan enlarged scale, of the device of Fig. 7.

Itfis'to be understood that the details of conform a continuous channelfor a liquid to be' treated,'which flows in a thin layer through a atbroad passage between the confronting flat surfacesof thin sheet metalplates, the outer surfaces of the platescforming the wall of a. pas-`sage on each side of eachchannel, for a liquidwhich is maintained at atemperature higher or lower than that of thel'liquid to be treated.

Each unit consists of two plates I', each plate having a continuous'recess 2 pressed therein substantially parallel with its edges toreceive a gasket 3 which maybe made of rubber or other suitablematerial. Near each end.. each plate is provided with one or moreperforations or passages 4. In Fig. 3, two circular perforations areshown asspaced apart symmetrically, the metal surrounding each vof theperforations being l5 struck up as a frusto-conical projection 5. Theseprojections being equally spaced from the central line of the plates andequally spaced from the end willregister with each other when the platesare placed back to back and will serve to l0 fix the distance betweenthe plates. Transversely corrugated or wavy strips of metal 6 arearranged longitudinally and transversely of the plates I between theribs Iformed by pressing the recess 2 into the metal and-these strips` 6may be welded or soldered to the plates I. 'I'he meeting rims of theprojections 5 will also be welded or solderedtogether to form aliquid-tight joint around the passages l. In apparatus in which 'theliquid is to be under considerable 20 pressure, an additional brace forthe central portion of the plates may be provided by securing a wavystrip 8 longitudinally between the two plates of each unit, as indicatedin Fig. 5, this strip being omitted in Figs. 1 and 4. 25

The end pieces 9 are preferably of cast metal such as aluminum, or ofoneof the light alloys, each member having one surface iiat and formed witha recess I0 corresponding in size and position with that of the recess 2in the plate which 30 will confront it when the units are assembled.Near-one end, each end piece has a recess I.I of considerable transverseextent. The opposite surface of each member 9 is formed withstrengthening ribs 'I2 and with a hollow boss I3 35 to receive an inlettube I4 or an outlet tube Il', as the member 9 maybe used at one end orthe other of the series of plate units. In Fig. 5, the 4boss I3 for theinlet tube Il is at the top, and

it has secured therein a stuiling box fitting I5 4o externally threadedat I6 to receive a gland I1 having a central cylindrical portion I8adapted lto bear `upon packing I9 within a. recess in the fitting I5surrounding the tube Il.y The bottom 'end piece has a short length tubeIl' secured v45 within the boss I3 to project an .inch or sov out of theboss, the amountof projection being suficient to bring the outer end ofthe tube Il' about midway of the length of arubber tube 2l held within arecess in a anged tting 2l se- 50 cured upon the-bottom of a tank 22.The ex' terior of the fitting 2I is threaded tor'eceive a hollow nut 23which bears upon a gland 24 tocompress the tube 20 upon the ends ofthemetal- 'tubes Il and I4',

as will be' explained herein- 55 the gasket 3 with the passage orpassages 4 at the end of the member 9 remote from the recess The uppersurface of this unit will have a recess 2 in 'which another gasket 3will be placed,

to receive a second unit of two plates which will be set with itspassage or passages 4 at the'same end as the recess and remote from thepassage or passages 4 of the first unit. This'procedure willvbe'continued with thev passages alternating between the two ends untila suiicient number .of units have been' used to provide the desiredlength of channel, whereupon the top end piece 9 will be set upon thegasket of the top unitwith its recess remote from the passage 4 of theuppermost unit. When an odd number of units is used, as for example,`the three units used in the assembly illustrated in Fig. 5the inlet andoutlet tubes will be at the same endl of the assembly as clearly shownin Fig. 1, but when the units are even in number, as shown in Figs. 4and 7, the inlet tube will be atone end and the outlet tube at the otherend.

Liquid entering through the tube I4 'atthe top in Fig. 5 and'passingthrough the bore 25 will encounter a solid plate I opposite the recessand will flow in a thin sheet through the narrow space between the endpiece and the top plate until it reaches the passage 4 at the other end.

'Opposite the passage 4, the solid plate I of the next lower unit-willcause the liquid to, flow through the space between the units ,until 'itreachesthe next passage 4 at the remote end, and so on to the lowermostunit, where the lower end piece 9 directs the flow to the recess |I andthrough the bore to the outlet tube I4'. The space between theconfronting surfaces of the plates of two adjacent units is determinedby the thickness of the gaskets 3 and such, gaskets may of course bemade of different thicknesses to prol receive sections 21 of largerpipes, which may be secured to the pipes 26 by setscrews 28. The

. sections 21 are connected in pairs by transversely arranged angle ironbrackets 29 which may be welded'to the sections 21 onl opposite sidesthere- -of to form ilat supporting surfaces for the tanks 22, 36, 'and3|.

- In each tank, an assembly of plate units and end plecesis set with theoutlet tube I4 in the fitting 2| and with the central portion of thelower end piece directly above the brackets 29. A clam screw `32operating in a nut 33 held centrally Within oppositely extending arms 34bears vwithin a recess 35 in the upper surface of the.

rib I2.' The outer ends ofthe arms 34 are formed as hooks to engage-thepipes-26 beneath the sec-` tions 21, so that when the screw is turned bythe handle 36, the sections 21 will resist upward movement of the armsandV thescrew will act to force the top end piece 9 down upon the unitsunderneath, compressing all of the gaskets 3 and holding the assemblysecurely in place in the tank. A rubber gasket 31 surrounding the tubeI4 beneath the boss I3 serves as aY water seal as well as assisting insupporting the boss upon the floor of the tank. Legs 38 at the cornersof the low'er end member .may be used to prevent tilting of theassembly.

While the assemblies are being placed within thetanks, they may be heldtogether by any temporary clamping means and the tubes I4 and I4 will befree to be slid within the stufling boxes before the glands and nuts aretightened to clamp the packing on the tubes. the tanks will besuiiicient -to permitthe removal -and replacement of the plateassemblies without disturbing the position oi the tanks or of theirsupporting brackets.

Each tank is arranged for the circulation of a liquid therethroughentering through the inlet pipes 39, passingthrough the plate unitsbetween the plates I through the spaces provided bythe corrugated strips6 and-out at the other side of the tank through outlet pipes .40preferably of` The space between I Since the arrangement shown in Fig. 1is primarily meant for use in pasteurization of milk, the tank 22 issupplied with water'heated 'to a temperature slightly above 142 by anelectric heater .unit 43 mounted within a small tank 44 and controlledby a thermostat 45 `having its plug securedwlthin the T 46 in theoutflow side' of the.' circuit, and a'pump 41 acting to force the heatedwater through the pipe 48 to the inlet pipes 39 of the tank.

The lowermost tank, 3|, is arranged to be supplied with a brinemaintained at a temperature just above freezing in avrefrigerator (notshown) from which the pipe 49 leads to the pump 50 which forces thebrine through pipe 5| to the inlet pipes 39' of the tank 3|, theoverflow pipe 52 returning the brine tothe refrigeratlng means forfurther cooling. Both circulating pumpsmay be driven' by a common motor53.

Milk entering the tube I4, preferably from a suitable strainer, (notshownin Fig. 1 but ,findicated at 9| in Fig. 7), will flow by thepressure of gravity back and forth through the thin spaces between theexterior surfaces of the units, receiving heat, from the heated waterflowing through the units, and since this heat is always kept below theboilingpoint, there is no possibility of the milk being cooked at anypoint during its ow through the pasteurizing assembly. The rate of owwill be regulated to make the time of treatment as long as may benecessary. The-number of units may be increased at will for greatercapacity of the assembly without other changes in the system. A H

From the pasteurizingv tank, the milk will flow down into the assemblyinthe cooling tank 30 to be reduced in temperature from |42 to that of thewater system, andfrom the tank.3||. the

cooled will flow into the assembly the bottom tank 3l, where the'brinemay bemade to chill it to as low a temperature as is desirable.

While the valve l which regulates the flow of the milk is shown lasdischarging into the open -top'of a milk can 5 5, it will be evidentthat it may lead to a bottling device of any suitable kind, so that themilklwill not be exposed to the air from the time it is strained untilit enters the bottles or the storage can or tank.

y It may here be 'remarked that the ordinary cooler formilk at presentincommon use, in which milk ows'from a strainer over a series of coolingpipes exposed to the air of a dairy, serves to add to the vstrained milkduring the cooling process all of the moisture condensed from thesurrounding air, together with bacteria, fungi, and perhaps also insectsthat may be in the air, whereas the present device serves to exclude allair and protects the milk during the whole process of heating andcooling and chilling.

I'he modification shown in Fig. 4 is intendedfor use in carbonatingbeverages, the apparatus being arranged to introduce the gas into coldliquid under pressure while maintaining a temperature as low as ispermitted short of freezing. The assembly illustrated has six plateunits,'which may be exactly the same in construction as those shown on alarge scale in Fig. 5. In view of the fact that the liquids used forcarbonating are not subject to rapid deterioration and that dailycleaning of the plates is not necessary, the connections may be madeless readily removable than in the apparatus just described for use withmilk. The end pieces 9 are shown as clamped upon the intermediate unitsby two clamp hoops 56, one

near each end, andeach having a clamp screw 32 with a handle 36. Theclamps will be put in place on the assembly before it is inserted intothe tank and no further clamping means will be required to hold it inthetank.

A tube 51 screws into theboss I3 and is centrallythreaded to receive alock nut 58 inside 7 the tank 59 and a lock-nut 60 outside of the tank,

with a rubber gasket or 'washer forming a water seal between the tubeand the tank. Upon the lower end of the tube 51 is screwed a valvefitting 6I having a nozzle 62 regulated by a needle 63.

4Below thenozzle is an inlet to receive a tube 34 connected with anysuitable source of carbon dioxide under pressure, and above the nozzle62 is an inlet for a cold liquid to be carbonated, supplied by a pipe 65leading from a suitable container. Neither the containerfor-'the liquidnor the carbon dioxide gas tank is illustrated since perature as low asnecessary to obtain the desired degree of carbonation. By arranging thegas to enter the previously cooled andpartially carbonated liquid at thepoint-of entry into the apparatus wherein the gas and liquid are forcedto flow a considerable distance while constantly being cooled close 'tothe freezing point, the maximum degree of carbonation will be reachedfor the pressures employed.

In the devices Ashown in Figs. 1, 4, and 5, the end pieces 9 form onewall of the channel forV the liquid both at the intake and at the outletend. When the end pieces'are of cast aluminum 3 or of certain lightmetal alloysg'the liquid treated or theliquid forced through forcleansing the system may adversely affect the exposed metallic surface,and even wheny there is noA such trouble because of the liquid, therough exterior left by the. casting process will usually requiremachining to provide a smooth surface suitable for cleaning. Themodification shown in Fig. 6 provides a separate -sheet metal end plate61 having a funnel-shaped inlet or outlet portion 68 which extendsthrough the cast end member 69 intoa rubber tube 29 held-within the bossI3 having a fitting I5, a gland 24, and a hollow nut 23, all of whichmay be. identical in construction and function with the parts similarlynumbered in Fig. 5.

vIn this modmcationfftne1iquid \does not come into contact with the castmetal of the end piece 69 which serves merely as a backing for the sheetmetal plate 61 and as a clamping member for the assembly -of pairs ofplates I connected by passages 4 .and wavy strips 6 as in the originalform. The gaskets 10 in this modification are shown as moulded i'n adiamond shaped cross section and as having thin lateral flanges or finsextending between the plates and acting as a means for determining thespace by which the plate surfaces. shall be separated when assembled,and thus regulating the thickness of the flowing film or sheet ofliquid.

Instead of providing a separatesheet metal tank to receive theheat-transfer assembly, the end members may be modified to form a closed-chamber through which c ooling or heating liquid may be forced morerapidly under greater pressure. .Such a modification is illustrated inFigs. '7 and 8 in a'form intended for pasteurizing milk.

The lower end member may consist of a rell atively fiat cast plate 12provided with a plurality of locking bolts 13 pivoted on lugs 14 andhaving -wing nuts 15 for engagement with the tops of spaced lugs 16formed upon the outer surface of the top end member 11 which is made inthe :form of a chamber of sumcient size to hold a plurality of sheetmetal plate units 18 which may be identical with those'previously shownand described in the other embodiments of the invention, but areillustrated in a slightly different form. As in the modification showninFig. 6, separate sheet metal plates 19 are used at both the top andbottom to prevent the liquid from .coming into contact with the endmembers 12 or 11, these plates 19 having funnel-shaped inlet or outletpassages 80, 80' extending intov rubber f tubes .29 held in bosses I3which have the same fittings and nuts asin the other types.

Ribs 8| extend longitudinally .of the end members in the direction of owto support the end plates 19 and to provide channels 82 between the ribsfor the heating or cooling uid. vThe gasvkets 33 between the plate unitsare shown as having iiat sides with rounded ends provided with .ns 84similar tofthe fins 1I of the gaskets 10 of Fig. 6. Instead ofcorrugated strips as in the other forms, the longitudinal membersbetween the plate ribs at the sides wherel a flow of liquid is notdesired may be ,of an oblong tubular form as shown at 85. while thetransverse strips '86 kwhich separate the ends of the plates of eachunit may be of zigzag or chevroned form tofpernit passage of liquid.-

The heating or cooling liquid enters" the base through a pipe 81v andleavesgat the'other end yat the top of a tube 33 which leads to theVdis- 'harge pipe 39 secured in the base at the end u remote from thepipe 81, neither pipe interfering in any way with the, removal orreplacement of the top member 11.

The vertical plane of section for the portion to the left of thev brokenline in Fig. 8 passes through the inlet tube 80, and the plane .ofsection forftheportion at" the right of the broken` line is to the rightof the outlet 4 tube in Fig. 7, with the ribs 91,/ the ends of theunits, and the tube 88 all seen in elevation, with the top of the memberTI partly broken laway. -The scale of Fig. 8 is one and a half timesthat of Fig. 7.

A gasket 90 in a channel around the periphery of the end member 12receives the edge of the side walls of the member Tl and the lockingbolts 13 draw the member 'l1 toward the member 12 to cause compressionof all the gaskets to hold the entire assembly liquid-tight.

When this formof device is used for p asteurizingvmilk, a strainer 9|supported above the upper assembly is connected by a tube 92 with theinlet passage 80 at the top of member-11 so that milk may ow back andforth through this pasteurizing assembly and out at the bottompassagell' in member 12, whence a tube 93 leads it into the top-of thecooling assembly beneath. This cooling assembly 94 maybe a duplicateofthe pasteurizing assembly and may be followed by a still lower chillingassembly as shown in Fig. 1. There will, of course, be automatic devicesfor heating the water in the pasteurizing assembly and for circulatingthe chilling brine, .but since these are fullysuggested in Fig. 1, theyhave lbeen left the recess by a passage for liquid.

2. A h e'at exchange-apparatusin which a plurality of unitsconstructedas in claim 1 are assembledfin a series with gaskets within the recessesseparating the units to provide a continuous 'channel through theassembly, and end membersclamped upon the assembly of units to hold themin assembled relation, one of said end members being formed to surroundthe end and sides of the assembly and cooperating with l'the other 'endmember to form a closed chamber fo the passageof a heat exchange liquid.

3. A heat'exchange unit comprising a pair of sheet metal plates eachhaving a peripheral rib embossed on one surface and forming acorresponding recess on the other surface and each having at one endinward from the rib a portion struck upward toward the side with the riband connected with the corresponding struck up por-A tion of the otherAplate of the pair to form a passage' for a liquid, and-meansvinterposed be' l' tween the lribs and connected therewith to hold theplates together.

4. A heat exchange unitl comprising a pair of sheet metalplates eachhaving a rib embossed on one surface near the periphery and forming arecess to receive a gasket on the other surface, wavy metal stripsbetween the ribs and secured thereto at theircontact points to hold themtogether and to lprovide spaces for liquid, and a liquid-tightconnectionbetween the plates forming a passage for a liquid.

5. A device in which a plurality of units constructed -as in claim 4 areassembled in a series with gaskets tted within the recesses to form acontinuous liquid passage through the series.`

and end members clamped upon the ends of the series to hold the units inassembled relation, said end members being provided with inlet andoutlet ports for liquid communicating with the liquid passage throughthe series.

6. A heat exchange apparatus comprising a plurality of sheet metalplates each having a shallow depression adjacent to the periphery'of theplate to receive a gasket, gasketsy mounted within the depressions andhaving a thickness greater than twice the depth of the depressionwhereby to separate the plates to form a thin passage betweenconfronting surfaces of two plates when assembled opposite each otherwith the gasket in the depressions, and means connecting the two vplatesbetween gaskets in pairs, back to back, one of the connecting means foreach pair of plates providing a passage for a liquid, and end membersclamped upon the units to hold them in assembled relation, said endmembers being provided with inlet and outlet ports forliqquidcommunicating with the liquid. passage Y formed by theplatesl andgaskets.

7. In a pasteurizena plurality of similar superposed `assemblies eachcomprising a plurality of heat transfer'units connected to form aconpasteurized, the uppermost assembly being provided withl means forconstant supply of heated liquid and with meansfor automaticallymaintaining the temperature of the heated liquid within a limited rangeabove the point of pasteurization. and below the boiling point, a lowerassembly provided with means for a constant supply of a coolir'igliquid,and a still lower assembly provided with means for a constant supply ofa refrigerant liquid, whereby a liquid to be pasteurized may descend bygravity through a heat transfer means adapted to raise its temperatureto the pasteurizing pointbut below an injurious temperature, thencethrough a. heat transfer `means adapted to remove a great part of thevheat, and thence through a final assembly adapted to chill thepasteurized liquid to a desired low temperature.

FRANK J. FE'I'I'E.

' tinuous channel for the ilow of a liquid to bev

